A gas turbine or compressor blade comprises an aerofoil, defined by a convex outer surface or suction side and a concave inner surface or pressure side, these being joined together at their upstream ends by a leading edge and at their downstream ends by a trailing edge for the gases. The pressure side and the suction side terminate on a platform which may be provided with a blade root of the dovetail or fir-tree type intended to be inserted into a corresponding slot in a rotor disc of the gas turbine or compressor, when this is a rotor blade or moving blade.
In general, the platform has a fairing that extends towards the upstream end from the leading edge and a fairing that extends towards the downstream end from the trailing edge. The upstream and downstream fairings of the blade platforms serve, in conjunction with stator elements of the gas turbine or compressor, to limit, by a baffle effect, the flow of gas from the inside of the turbine or compressor radially towards the pressure and suction sides of the blades and, conversely, from the pressure and suction sides of the blades into the gas turbine or compressor. The upstream and downstream fairings therefore provide an important function, this having a direct influence on the head losses of the gas turbine or compressor and therefore on their efficiency.
In operation, the downstream fairings of the blade platforms, which are exposed to high temperatures, expand and deform relative to the aerofoils, thereby creating high stresses at the junctions between the blade aerofoils and the platforms.
These stresses are liable to weaken the blades and reduce their lifetime.
The object of the invention is in particular to provide a simple, inexpensive and effective solution to this problem.